-89.41% is the change from 170 to 18
Calculation steps:
[( 18 - 170 ) ÷ 170] x 100 = -89.41%
Formula
Percentage change = [(18 - 170) / 170] x 100
Subtract the new number by the original number
18 - 170 = -152
-152 ÷ 170 = -0.8941176470588236
-0.8941176470588236 x 100 = -89.41%